计算:(-a-b)^2-(1/4a-2/3b)^2

问题描述:

计算:(-a-b)^2-(1/4a-2/3b)^2

(-a-b)^2-(1/4a-2/3b)^2
=a^2-2ab+b^2-1/16a^2+1/3ab-4/9b^2
=15/16a^2-5/3ab+5/9b^2